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Proceedings Paper

Modulation of PDT-induced apoptosis by protein kinases and phosphatases
Author(s): Yu Luo; Chi Kwong Chang; David Kessel
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Paper Abstract

Photodynamic therapy of neoplastic cell lines can lead to the rapid initiation of apoptosis, a mode of cell death that results in a characteristic pattern of cellular and DNA fragmentation. In this study, we examine the effects of protein tyrosine- and serine/threonine phosphatases and kinases on the fragmentation of DNA to 50 kb and photodynamic effects of lysosomal and mitochondrial photosensitizers on murine leukemia P388 cells. The data are consistent with the proposal that maintenance of phosphorylated tyrosine residues is essential for the PDT- induced processing of 50 kb DNA to nucleosomes, while maintenance of serine phosphorylation inhibits such processing. Factors involved in chromatin fragmentation to 50 kb particles have yet to be elucidated. Several agents which mediate membrane photodamage mimic the effect of protein serine/threonine phosphatase inhibitors, i.e., they inhibit further processing of the 50 kb DNA formed as a consequence of lysosomal or mitochondrial photodamage. These results indicate that even the rapid initiation of apoptosis by PDT is modulated by phosphatase and kinase activities.

Paper Details

Date Published: 2 April 1996
PDF: 6 pages
Proc. SPIE 2675, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy V, (2 April 1996); doi: 10.1117/12.237530
Show Author Affiliations
Yu Luo, Wayne State Univ. School of Medicine (United States)
Chi Kwong Chang, Michigan State Univ. (United States)
David Kessel, Wayne State Univ. School of Medicine (United States)


Published in SPIE Proceedings Vol. 2675:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy V
Thomas J. Dougherty, Editor(s)

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